Mild depressive symptoms are associated with gait impairment in early Parkinson's disease

The association between nonmotor characteristics and gait in Parkinson's disease (PD) is well established, particularly the role of cognition. Evidence is emerging that depression, an underrecognized symptom in PD is also associated with gait impairment. This cross-sectional study examined the association between depressive symptomatology and gait in early PD. Depression was measured with the Geriatric Depression Scale (GDS), disease severity with the Unified Parkinson's Disease Rating Scale III, and cognition with the Mini Mental Status Examination. Gait speed and gait variability were measured using a 7-m walkway (GAITRite). Linear regression was used to examine the association between depression and gait for PD and controls, controlling for age, cognition, and severity. PD participants who presented with clinically relevant depressive symptoms (GDS 5) were compared with those who scored < 5. One hundred and twenty-two people with newly diagnosed PD and 184 controls were assessed. Depression scores were significantly higher for PD patients than for controls (P < .001), although neither group presented with clinically relevant symptomatology (mean [SD] for PD, 2.7 [2.3]; for controls, 1.1 [1.8]). For gait speed there was a main effect for depression (P < .001) and a group x depression interaction that approached significance (P = .054). For gait variability there was a main effect for depression (P < .01). PD participants with GDS scores 5 had a slower and more variable gait. Very mild depressive symptoms are associated with gait disturbance in early PD. Depression may be a marker for degeneration in nondopaminergic systems in early PD and influence mechanisms of gait disturbance. (c) 2013 Movement Disorder Society